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Song P.,Enbridge Inc. | Cheng J.J.R.,University of Alberta | Ironside S.,Enbridge Inc. | Skibinsky D.,Alliance Pipeline Ltd.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2010

Field experience showed that repairing wrinkles developed on energy pipelines using steel sleeves is an efficient and cost effective method. Based on the previous successful numerical simulations of a field wrinkle sleeve repair work, a parametric study was conducted by using Finite Element (FE) method to further investigate the effectiveness of the sleeve repair technique. The FE package ABAQUS 6.4 was utilized in conducting the parametric study. The parameters studied include the length, the thickness, and the material properties of the sleeve, and the thickness of the collar, which is used to fit between the wrinkled pipe and the repairing sleeve. The range of the parameters studied covers the most commonly used typical values in the pipeline industry. Two phases were used in carrying out the parametric study. In Phase I, the parameter that plays the most important role in determining the behavior of the wrinkle sleeve repair system (WSRS) was studied. It is found this parameter is the length of the repairing sleeve. Brief discussion was given regarding the way this parameter affects the behavior of the pipe using the WSRS. In Phase II, based on the results from the Phase I study, the effects of other parameters were investigated through a series of FE analyses. Conclusions were drawn and recommendations for future wrinkle sleeve repair work were given based on the results of the parametric study. Copyright © 2010 by ASME.

Botros K.K.,Nova Chemicals Corporation | Geerligs J.,Nova Chemicals Corporation | Rothwell B.,Brian Rothwell Consulting Inc. | Carlson L.,Alliance Pipeline Ltd. | And 2 more authors.
International Journal of Pressure Vessels and Piping | Year: 2010

The control of propagating ductile (or tearing) fracture is a fundamental requirement in the fracture control design of pipelines. The Battelle two-curve method developed in the early 1970s still forms the basis of the analytical framework used throughout the industry. GASDECOM is typically used for calculating decompression speed, and idealizes the decompression process as isentropic and one-dimensional, taking no account of frictional effects. While this approximation appears not to have been a major issue for large-diameter pipes and for moderate pressures (up to 12 MPa), there have been several recent full-scale burst tests at higher pressures and smaller diameters for which the measured decompression velocity has deviated progressively from the predicted values, in general towards lower velocities. The present research was focused on determining whether pipe diameter was a major factor that could limit the applicability of frictionless models such as GASDECOM. Since potential diameter effects are primarily related to wall friction, which in turn is related to the ratio of surface roughness-to-diameter, an experimental approach was developed based on keeping the diameter constant, at a sufficiently small value to allow for an economical experimental arrangement, and varying the internal roughness. A series of tests covering a range of nominal initial pressures from 10 to 21 MPa, and involving a very lean gas and three progressively richer compositions, were conducted using two specialized high-pressure shock tubes (42 m long, I.D. = 38.1 mm). The first is honed to an extremely smooth surface finish, in order to minimize frictional effects and better simulate the behaviour of larger-diameter pipelines, while the second has a higher internal surface roughness. The results show that decompression wave speeds in the rough tube are consistently slower than those in the smooth tube under the same conditions of mixture composition and initial pressure & temperature. Preliminary analysis based on perturbation theory and the fundamental momentum equation indicates that the primary reason for the slower decompression wave speed in the rough tube is the higher spatial gradient of pressure pertaining to the decompression wave dynamics, particularly at lower pressure ratios and higher gas velocities. The magnitude of the effect of the slower decompression speed on arrest toughness was then evaluated by a comparison involving several hypothetical pipeline designs, and was found to be potentially significant for pipe sizes DN 450 and smaller. © 2010 Elsevier Ltd.

Schapira D.O.S.,Alliance Pipeline Ltd.
Proceedings of the Biennial International Pipeline Conference, IPC | Year: 2014

Alliance Pipeline operates an integrated Canadian and U.S. high-pressure, rich natural gas transmission pipeline system. Rich natural gas pipelines are unique in that the product transported in these pipelines contains greater amounts of higher molecular weight hydrocarbons than would be transported in a dry natural gas pipeline. The specifications for gas quality however are very similar and require the product to contain less than sixty five mg/m3 water, no free liquids and/or objectionable materials such as bacteria, ashphaltene, gum, etc. The acid gases, carbon dioxide and hydrogen sulphide, are also required to be below certain values (see Table 1). Corrosion is not expected to occur under these conditions due to the lack of free water available for the development of an electrochemical corrosion cell. However, there are instances where the gas quality may vary and this gas enters facility piping for short periods of time. A method has been developed by Pipeline Research Council International (PRCI) to determine the internal corrosion susceptibility for dry gas natural gas there are currently no industry pipelines but accepted models which determine the internal corrosion susceptibility for high energy natural gas (HENG) pipeline systems. Accordingly, it is important for operators of pipelines with high energy natural gas (HENG) to collect and analyze these off specification events and develop a method to determine the relative impact on internal corrosion susceptibility. It is perhaps more important for operators to use this method to develop a strategy to prioritize facility piping for inspection and confirm the absence of internal corrosion. An Internal Corrosion Susceptibility Assessment (ICSA) method has been developed for HENG which considers off specification water, carbon dioxide, and hydrogen sulphide contents in the HENG. The analysis has been enhanced to also consider low temperature operation and hydrocarbon dew-point variations. The model has been effectively trialed over the last number of years to prioritize inspections and has been further tested against PRCI research and models developed for dry gas internal corrosion susceptibility. All internal corrosion models need to identify free water as prime contributor to susceptibility, thus the subject model is considered adaptable to other gas pipeline systems. This paper discusses the methods used to develop the model, the challenges encountered and results of the field inspections conducted. Copyright © 2014 by ASME.

Alliance Pipeline L.P. and Alliance Pipeline Inc. | Date: 2003-01-28

natural gas. operation and management of natural gas and natural gas liquid pipelines and related equipment, compressor stations, valve facilities and metering stations for others. repair and maintenance of natural gas and natural gas liquid pipelines and related equipment, compressor stations, valve facilities, and metering stations. pipeline transmission of natural gas and natural gas liquids in and from metering stations.

Botros K.K.,Nova Chemicals Corporation | Geerligs J.,Nova Chemicals Corporation | Carlson L.,Alliance Pipeline Ltd. | Reed M.,Alliance Pipeline Ltd.
International Journal of Pressure Vessels and Piping | Year: 2013

One of the fundamental requirements of the design of pipelines is the control of propagating ductile fracture, in which the Battelle two-curve method still forms the basis of the analytical framework used throughout the industry. The GASDECOM (GAS DECOMpression) tool is typically used for calculating decompression wave speed, which is one of these two curves. It uses the BWRS (Benedict-Webb-Rubin-Starling) equation of state to idealize the decompression process as isentropic and one-dimensional. While this equation of state was developed and validated against a quite restricted range of gas compositions, GASDECOM continues to perform relatively well for compositions slightly outside the original range of BWRS. The present research was focused on examining the performance of GASDECOM for mixture compositions up to a High (gross) Heating Value (HHV) of 58MJ/m3. Four tests were conducted using a specialized high pressure shock tube (42m long, I.D.=38.1mm) to experimentally determine the decompression wave speeds and compare them to the predictions by GASDECOM. Two tests were conducted on a gas mixture of HHV=52MJ/m3 and the other two on even richer gas mixture of HHV=58MJ/m3, all were from nominal initial pressures of 15MPa and initial temperatures of 40°C. The results from these tests show that decompression wave speeds are consistent with predictions of GASDECOM for gases of HHV typical of the previously validated range of BWRS. Predictions of the saturation pressure represented by the plateau pressure in the decompression wave speed curve were also in good agreement with measurements despite the fact that they occurred close to the critical point of the respective mixture compositions. © 2013 Elsevier Ltd.

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